ARC-Fire Install

Install Steps:

1. Replace stock mil-spec trigger shoe with precut trigger from kit. Reuse trigger spring, disconnector spring, and disconnector.
2. Reinstall hammer and hammer spring.
3. Make sure hammer is cocked. (If the hammer isn't cocked, you will not be able to install safety selector parts)
4. Attach ambi selector to detent bar.
5. Push detent bar through right side of lower and through the transfer lever. The tip of the transfer lever should point away from the hammer and towards the rear of the lower.
6. Rotate selector to semi position.
7. Install mil-spec detent and grip with detent spring.
8. Check positions click with ambi selector.
9. Install cam with the reset surface/groove at the bottom and closest to the transfer lever (CRITICAL).
10. Install primary selector in same position as ambi selector (semi preferred).
11. Install remaining screw.
12. Function check, making sure the transfer lever is kept forward.

Other info:

• You MUST use a cut trigger according to Hoffman Tactical’s specs.
  
  
• If you experience heavy trigger pull, the trigger may be slightly out of spec. Remove it and then lightly sand/polish the rounded corner and re-test. Be careful to not remove too much material. You may also utilize 3D-printed GO/NO-GO jigs to verify fitment.
  
  
• This is not compatible with AR-10/LR-308, AR 12GA, or any platform not using a typical FA M16 BCG. Some other platforms utilize additional parts for compatibility (i.e. AR22, MP5, MCX/MPX, JAKL, etc.).
• When assembled, if the BCG binds/locks up when pulled to the rear, this typically indicates a clearance issue between the lever, BCG, and/or upper. First, verify the lower is not a high shelf lower (we have a list on our FAQ, but always double check your own part). If it is a low shelf lower, you may either grind the top of the lever until it clears or you may cut the rear of the upper opening back (preferred). This may affect the integrity of the lever, so we don’t recommend that and we will not replace the lever if it fails after that modification.
  
  
• When first used, if you experience light primer strikes or hammer follow symptoms (typically 1-2 rounds are fired then the trigger is dead), you should replace the buffer with an H2 or H3 buffer. You may also adjust the gas block, if equipped. This resolves the issue in 99% of scenarios and we recommend using a H2 buffer to start.
  
  
• When used in a PCC, you may need to cut the bolt weight to clear the lever (see Picture 5 on AR Upper Troubleshooting HERE). You may also replace it with a KAK Industry tungsten weight (preferred). It is also strongly recommended to use CMMG upper systems due to the radial delay BCG preventing OOB issues. If you do not use CMMG, ensure you increase total bolt+buffer weight to 23+ oz to avoid OOB issues.
  
  
• Some manufacturers utilize a “high shelf” receiver or some other block that will interfere with this system’s operation. We recommend avoiding lowers with this design (e.g. Colt, longer list on our FAQ, but always double check your own parts), but you may also cut this shelf out of the way with a Dremel if desired. We do not guarantee fitment.
  
  
• Note: All products are recommended to be installed by a qualified gunsmith.